1. Technical Field
The present disclosure relates to an ultrasonic flowmeter.
2. Related Art
A clamp-on type ultrasonic flowmeter has been widely used in various fields for the following reasons, for example. The clamp-on type ultrasonic flowmeter can be installed afterward in the existing pipeline. The clamp-on type ultrasonic flowmeter has a transducer portion for transmitting and receiving ultrasonic signals attached outside the pipeline to prevent pressure loss. The clamp-on type ultrasonic flowmeter can easily measure even corrosive fluid and/or high-pressure fluid.
FIGS. 10A and 10B are diagrams illustrating the structure of an exemplary clamp-on type ultrasonic flowmeter in the related art (refer to, for example, Japanese Patent No. 3043758). Specifically, FIG. 10A is a diagram illustrating the entire structure of the flowmeter, and FIG. 10B is a partial cross-sectional view of a transducer 4 in FIG. 10A. The ultrasonic flowmeter includes a first bracket 3 and a second bracket 5 on the upper part of a pipeline 1 in a pipe axis direction. The first bracket 3 is attached with a first hooded ultrasonic transducer 2, and the second bracket 5 is attached with a second hooded ultrasonic transducer 4. These first and second brackets 3 and 5 are fixed on the pipeline 1 in an axial direction thereof through metal bands 6 and 7, respectively, to maintain a predetermined positional relation therebetween.
As illustrated in FIG. 10B, each of the hooded transducers 2 and 4 houses a base 8 having a predetermined inclined surface on which an ultrasonic transducer 9 is attached.
The ultrasonic flowmeter configured as described above operates as follows. The first ultrasonic transducer 2, which is fixed on the pipeline 1, emits an ultrasonic wave from its ultrasonic transducer in a direction obliquely to the axis of the pipeline 1. The second ultrasonic transducer 4 is slid over the pipeline 1 to find out a suitable position thereof for allowing its ultrasonic transducer to receive the ultrasonic wave most efficiently, followed by being fixed on the resulting position.
FIG. 11 is a diagram illustrating the structure of another exemplary clamp-on type ultrasonic flowmeter in the related art (refer to, for example, JP-T-2011-501191). As illustrated in FIG. 11, the ultrasonic flowmeter 10 includes a plurality of leg portions 14 and a dial gauge 15. The leg portions 14 are disposed with spaces therebetween and are in contact with an outer peripheral surface 13 of a predetermined portion 12 of a pipe 11. The dial gauge 15 is disposed between the leg portions 14. The dial gauge 15 is configured to indicate the radius of curvature at each of a plurality of positions measured from a measurement reference point in a circumferential direction along the outer peripheral surface 13. The curvature radius data at the positions, which are measured by the dial gauge 15, and the thickness data of the pipe, which are measured separately, are transmitted to a processor 16. These data are used, for example, in calculation to determine the horizontal cross-sectional area of the predetermined portion 12 of the pipe 11.